blob: d1172aec0b82774a0c7dc61ebf2d6675a6ae00f7 [file] [log] [blame]
// Copyright 2015 PDFium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
#include "core/fxcodec/jbig2/JBig2_GrrdProc.h"
#include <memory>
#include "core/fxcodec/jbig2/JBig2_ArithDecoder.h"
#include "core/fxcodec/jbig2/JBig2_BitStream.h"
#include "core/fxcodec/jbig2/JBig2_Image.h"
CJBig2_GRRDProc::CJBig2_GRRDProc() = default;
CJBig2_GRRDProc::~CJBig2_GRRDProc() = default;
std::unique_ptr<CJBig2_Image> CJBig2_GRRDProc::Decode(
CJBig2_ArithDecoder* pArithDecoder,
JBig2ArithCtx* grContext) {
if (!CJBig2_Image::IsValidImageSize(GRW, GRH))
return std::make_unique<CJBig2_Image>(GRW, GRH);
if (!GRTEMPLATE) {
if ((GRAT[0] == -1) && (GRAT[1] == -1) && (GRAT[2] == -1) &&
(GRAT[3] == -1) && (GRREFERENCEDX == 0) &&
(GRW == (uint32_t)GRREFERENCE->width())) {
return DecodeTemplate0Opt(pArithDecoder, grContext);
}
return DecodeTemplate0Unopt(pArithDecoder, grContext);
}
if ((GRREFERENCEDX == 0) && (GRW == (uint32_t)GRREFERENCE->width()))
return DecodeTemplate1Opt(pArithDecoder, grContext);
return DecodeTemplate1Unopt(pArithDecoder, grContext);
}
std::unique_ptr<CJBig2_Image> CJBig2_GRRDProc::DecodeTemplate0Unopt(
CJBig2_ArithDecoder* pArithDecoder,
JBig2ArithCtx* grContext) {
auto GRREG = std::make_unique<CJBig2_Image>(GRW, GRH);
if (!GRREG->data())
return nullptr;
GRREG->Fill(0);
int LTP = 0;
for (uint32_t h = 0; h < GRH; h++) {
if (TPGRON) {
if (pArithDecoder->IsComplete())
return nullptr;
LTP = LTP ^ pArithDecoder->Decode(&grContext[0x0010]);
}
uint32_t lines[5];
lines[0] = GRREG->GetPixel(1, h - 1);
lines[0] |= GRREG->GetPixel(0, h - 1) << 1;
lines[1] = 0;
lines[2] = GRREFERENCE->GetPixel(-GRREFERENCEDX + 1, h - GRREFERENCEDY - 1);
lines[2] |= GRREFERENCE->GetPixel(-GRREFERENCEDX, h - GRREFERENCEDY - 1)
<< 1;
lines[3] = GRREFERENCE->GetPixel(-GRREFERENCEDX + 1, h - GRREFERENCEDY);
lines[3] |= GRREFERENCE->GetPixel(-GRREFERENCEDX, h - GRREFERENCEDY) << 1;
lines[3] |= GRREFERENCE->GetPixel(-GRREFERENCEDX - 1, h - GRREFERENCEDY)
<< 2;
lines[4] = GRREFERENCE->GetPixel(-GRREFERENCEDX + 1, h - GRREFERENCEDY + 1);
lines[4] |= GRREFERENCE->GetPixel(-GRREFERENCEDX, h - GRREFERENCEDY + 1)
<< 1;
lines[4] |= GRREFERENCE->GetPixel(-GRREFERENCEDX - 1, h - GRREFERENCEDY + 1)
<< 2;
if (!LTP) {
for (uint32_t w = 0; w < GRW; w++) {
uint32_t CONTEXT =
DecodeTemplate0UnoptCalculateContext(*GRREG, lines, w, h);
if (pArithDecoder->IsComplete())
return nullptr;
int bVal = pArithDecoder->Decode(&grContext[CONTEXT]);
DecodeTemplate0UnoptSetPixel(GRREG.get(), lines, w, h, bVal);
}
} else {
for (uint32_t w = 0; w < GRW; w++) {
int bVal = GRREFERENCE->GetPixel(w, h);
if (!(TPGRON && (bVal == GRREFERENCE->GetPixel(w - 1, h - 1)) &&
(bVal == GRREFERENCE->GetPixel(w, h - 1)) &&
(bVal == GRREFERENCE->GetPixel(w + 1, h - 1)) &&
(bVal == GRREFERENCE->GetPixel(w - 1, h)) &&
(bVal == GRREFERENCE->GetPixel(w + 1, h)) &&
(bVal == GRREFERENCE->GetPixel(w - 1, h + 1)) &&
(bVal == GRREFERENCE->GetPixel(w, h + 1)) &&
(bVal == GRREFERENCE->GetPixel(w + 1, h + 1)))) {
uint32_t CONTEXT =
DecodeTemplate0UnoptCalculateContext(*GRREG, lines, w, h);
if (pArithDecoder->IsComplete())
return nullptr;
bVal = pArithDecoder->Decode(&grContext[CONTEXT]);
}
DecodeTemplate0UnoptSetPixel(GRREG.get(), lines, w, h, bVal);
}
}
}
return GRREG;
}
uint32_t CJBig2_GRRDProc::DecodeTemplate0UnoptCalculateContext(
const CJBig2_Image& GRREG,
const uint32_t* lines,
uint32_t w,
uint32_t h) const {
uint32_t CONTEXT = lines[4];
CONTEXT |= lines[3] << 3;
CONTEXT |= lines[2] << 6;
CONTEXT |= GRREFERENCE->GetPixel(w - GRREFERENCEDX + GRAT[2],
h - GRREFERENCEDY + GRAT[3])
<< 8;
CONTEXT |= lines[1] << 9;
CONTEXT |= lines[0] << 10;
CONTEXT |= GRREG.GetPixel(w + GRAT[0], h + GRAT[1]) << 12;
return CONTEXT;
}
void CJBig2_GRRDProc::DecodeTemplate0UnoptSetPixel(CJBig2_Image* GRREG,
uint32_t* lines,
uint32_t w,
uint32_t h,
int bVal) {
GRREG->SetPixel(w, h, bVal);
lines[0] = ((lines[0] << 1) | GRREG->GetPixel(w + 2, h - 1)) & 0x03;
lines[1] = ((lines[1] << 1) | bVal) & 0x01;
lines[2] = ((lines[2] << 1) | GRREFERENCE->GetPixel(w - GRREFERENCEDX + 2,
h - GRREFERENCEDY - 1)) &
0x03;
lines[3] = ((lines[3] << 1) |
GRREFERENCE->GetPixel(w - GRREFERENCEDX + 2, h - GRREFERENCEDY)) &
0x07;
lines[4] = ((lines[4] << 1) | GRREFERENCE->GetPixel(w - GRREFERENCEDX + 2,
h - GRREFERENCEDY + 1)) &
0x07;
}
std::unique_ptr<CJBig2_Image> CJBig2_GRRDProc::DecodeTemplate0Opt(
CJBig2_ArithDecoder* pArithDecoder,
JBig2ArithCtx* grContext) {
if (!GRREFERENCE->data())
return nullptr;
int32_t iGRW = static_cast<int32_t>(GRW);
int32_t iGRH = static_cast<int32_t>(GRH);
auto GRREG = std::make_unique<CJBig2_Image>(iGRW, iGRH);
if (!GRREG->data())
return nullptr;
int LTP = 0;
uint8_t* pLine = GRREG->data();
uint8_t* pLineR = GRREFERENCE->data();
intptr_t nStride = GRREG->stride();
intptr_t nStrideR = GRREFERENCE->stride();
int32_t GRWR = GRREFERENCE->width();
int32_t GRHR = GRREFERENCE->height();
if (GRREFERENCEDY < -GRHR + 1 || GRREFERENCEDY > GRHR - 1)
GRREFERENCEDY = 0;
intptr_t nOffset = -GRREFERENCEDY * nStrideR;
for (int32_t h = 0; h < iGRH; h++) {
if (TPGRON) {
if (pArithDecoder->IsComplete())
return nullptr;
LTP = LTP ^ pArithDecoder->Decode(&grContext[0x0010]);
}
uint32_t line1 = (h > 0) ? pLine[-nStride] << 4 : 0;
int32_t reference_h = h - GRREFERENCEDY;
bool line1_r_ok = (reference_h > 0 && reference_h < GRHR + 1);
bool line2_r_ok = (reference_h > -1 && reference_h < GRHR);
bool line3_r_ok = (reference_h > -2 && reference_h < GRHR - 1);
uint32_t line1_r = line1_r_ok ? pLineR[nOffset - nStrideR] : 0;
uint32_t line2_r = line2_r_ok ? pLineR[nOffset] : 0;
uint32_t line3_r = line3_r_ok ? pLineR[nOffset + nStrideR] : 0;
if (!LTP) {
uint32_t CONTEXT = (line1 & 0x1c00) | (line1_r & 0x01c0) |
((line2_r >> 3) & 0x0038) | ((line3_r >> 6) & 0x0007);
for (int32_t w = 0; w < iGRW; w += 8) {
int32_t nBits = iGRW - w > 8 ? 8 : iGRW - w;
if (h > 0) {
line1 = (line1 << 8) |
(w + 8 < iGRW ? pLine[-nStride + (w >> 3) + 1] << 4 : 0);
}
if (h > GRHR + GRREFERENCEDY + 1) {
line1_r = 0;
line2_r = 0;
line3_r = 0;
} else {
if (line1_r_ok) {
line1_r =
(line1_r << 8) |
(w + 8 < GRWR ? pLineR[nOffset - nStrideR + (w >> 3) + 1] : 0);
}
if (line2_r_ok) {
line2_r = (line2_r << 8) |
(w + 8 < GRWR ? pLineR[nOffset + (w >> 3) + 1] : 0);
}
if (line3_r_ok) {
line3_r =
(line3_r << 8) |
(w + 8 < GRWR ? pLineR[nOffset + nStrideR + (w >> 3) + 1] : 0);
} else {
line3_r = 0;
}
}
uint8_t cVal = 0;
for (int32_t k = 0; k < nBits; k++) {
int bVal = pArithDecoder->Decode(&grContext[CONTEXT]);
cVal |= bVal << (7 - k);
CONTEXT = ((CONTEXT & 0x0cdb) << 1) | (bVal << 9) |
((line1 >> (7 - k)) & 0x0400) |
((line1_r >> (7 - k)) & 0x0040) |
((line2_r >> (10 - k)) & 0x0008) |
((line3_r >> (13 - k)) & 0x0001);
}
pLine[w >> 3] = cVal;
}
} else {
uint32_t CONTEXT = (line1 & 0x1c00) | (line1_r & 0x01c0) |
((line2_r >> 3) & 0x0038) | ((line3_r >> 6) & 0x0007);
for (int32_t w = 0; w < iGRW; w += 8) {
int32_t nBits = iGRW - w > 8 ? 8 : iGRW - w;
if (h > 0) {
line1 = (line1 << 8) |
(w + 8 < iGRW ? pLine[-nStride + (w >> 3) + 1] << 4 : 0);
}
if (line1_r_ok) {
line1_r =
(line1_r << 8) |
(w + 8 < GRWR ? pLineR[nOffset - nStrideR + (w >> 3) + 1] : 0);
}
if (line2_r_ok) {
line2_r = (line2_r << 8) |
(w + 8 < GRWR ? pLineR[nOffset + (w >> 3) + 1] : 0);
}
if (line3_r_ok) {
line3_r =
(line3_r << 8) |
(w + 8 < GRWR ? pLineR[nOffset + nStrideR + (w >> 3) + 1] : 0);
} else {
line3_r = 0;
}
uint8_t cVal = 0;
for (int32_t k = 0; k < nBits; k++) {
int bVal = GRREFERENCE->GetPixel(w + k, h);
if (!(TPGRON && (bVal == GRREFERENCE->GetPixel(w + k - 1, h - 1)) &&
(bVal == GRREFERENCE->GetPixel(w + k, h - 1)) &&
(bVal == GRREFERENCE->GetPixel(w + k + 1, h - 1)) &&
(bVal == GRREFERENCE->GetPixel(w + k - 1, h)) &&
(bVal == GRREFERENCE->GetPixel(w + k + 1, h)) &&
(bVal == GRREFERENCE->GetPixel(w + k - 1, h + 1)) &&
(bVal == GRREFERENCE->GetPixel(w + k, h + 1)) &&
(bVal == GRREFERENCE->GetPixel(w + k + 1, h + 1)))) {
if (pArithDecoder->IsComplete())
return nullptr;
bVal = pArithDecoder->Decode(&grContext[CONTEXT]);
}
cVal |= bVal << (7 - k);
CONTEXT = ((CONTEXT & 0x0cdb) << 1) | (bVal << 9) |
((line1 >> (7 - k)) & 0x0400) |
((line1_r >> (7 - k)) & 0x0040) |
((line2_r >> (10 - k)) & 0x0008) |
((line3_r >> (13 - k)) & 0x0001);
}
pLine[w >> 3] = cVal;
}
}
pLine += nStride;
if (h < GRHR + GRREFERENCEDY)
pLineR += nStrideR;
}
return GRREG;
}
std::unique_ptr<CJBig2_Image> CJBig2_GRRDProc::DecodeTemplate1Unopt(
CJBig2_ArithDecoder* pArithDecoder,
JBig2ArithCtx* grContext) {
auto GRREG = std::make_unique<CJBig2_Image>(GRW, GRH);
if (!GRREG->data())
return nullptr;
GRREG->Fill(0);
int LTP = 0;
for (uint32_t h = 0; h < GRH; h++) {
if (TPGRON) {
if (pArithDecoder->IsComplete())
return nullptr;
LTP = LTP ^ pArithDecoder->Decode(&grContext[0x0008]);
}
if (!LTP) {
uint32_t line1 = GRREG->GetPixel(1, h - 1);
line1 |= GRREG->GetPixel(0, h - 1) << 1;
line1 |= GRREG->GetPixel(-1, h - 1) << 2;
uint32_t line2 = 0;
uint32_t line3 =
GRREFERENCE->GetPixel(-GRREFERENCEDX, h - GRREFERENCEDY - 1);
uint32_t line4 =
GRREFERENCE->GetPixel(-GRREFERENCEDX + 1, h - GRREFERENCEDY);
line4 |= GRREFERENCE->GetPixel(-GRREFERENCEDX, h - GRREFERENCEDY) << 1;
line4 |= GRREFERENCE->GetPixel(-GRREFERENCEDX - 1, h - GRREFERENCEDY)
<< 2;
uint32_t line5 =
GRREFERENCE->GetPixel(-GRREFERENCEDX + 1, h - GRREFERENCEDY + 1);
line5 |= GRREFERENCE->GetPixel(-GRREFERENCEDX, h - GRREFERENCEDY + 1)
<< 1;
for (uint32_t w = 0; w < GRW; w++) {
uint32_t CONTEXT = line5;
CONTEXT |= line4 << 2;
CONTEXT |= line3 << 5;
CONTEXT |= line2 << 6;
CONTEXT |= line1 << 7;
if (pArithDecoder->IsComplete())
return nullptr;
int bVal = pArithDecoder->Decode(&grContext[CONTEXT]);
GRREG->SetPixel(w, h, bVal);
line1 = ((line1 << 1) | GRREG->GetPixel(w + 2, h - 1)) & 0x07;
line2 = ((line2 << 1) | bVal) & 0x01;
line3 = ((line3 << 1) | GRREFERENCE->GetPixel(w - GRREFERENCEDX + 1,
h - GRREFERENCEDY - 1)) &
0x01;
line4 = ((line4 << 1) | GRREFERENCE->GetPixel(w - GRREFERENCEDX + 2,
h - GRREFERENCEDY)) &
0x07;
line5 = ((line5 << 1) | GRREFERENCE->GetPixel(w - GRREFERENCEDX + 2,
h - GRREFERENCEDY + 1)) &
0x03;
}
} else {
uint32_t line1 = GRREG->GetPixel(1, h - 1);
line1 |= GRREG->GetPixel(0, h - 1) << 1;
line1 |= GRREG->GetPixel(-1, h - 1) << 2;
uint32_t line2 = 0;
uint32_t line3 =
GRREFERENCE->GetPixel(-GRREFERENCEDX, h - GRREFERENCEDY - 1);
uint32_t line4 =
GRREFERENCE->GetPixel(-GRREFERENCEDX + 1, h - GRREFERENCEDY);
line4 |= GRREFERENCE->GetPixel(-GRREFERENCEDX, h - GRREFERENCEDY) << 1;
line4 |= GRREFERENCE->GetPixel(-GRREFERENCEDX - 1, h - GRREFERENCEDY)
<< 2;
uint32_t line5 =
GRREFERENCE->GetPixel(-GRREFERENCEDX + 1, h - GRREFERENCEDY + 1);
line5 |= GRREFERENCE->GetPixel(-GRREFERENCEDX, h - GRREFERENCEDY + 1)
<< 1;
for (uint32_t w = 0; w < GRW; w++) {
int bVal = GRREFERENCE->GetPixel(w, h);
if (!(TPGRON && (bVal == GRREFERENCE->GetPixel(w - 1, h - 1)) &&
(bVal == GRREFERENCE->GetPixel(w, h - 1)) &&
(bVal == GRREFERENCE->GetPixel(w + 1, h - 1)) &&
(bVal == GRREFERENCE->GetPixel(w - 1, h)) &&
(bVal == GRREFERENCE->GetPixel(w + 1, h)) &&
(bVal == GRREFERENCE->GetPixel(w - 1, h + 1)) &&
(bVal == GRREFERENCE->GetPixel(w, h + 1)) &&
(bVal == GRREFERENCE->GetPixel(w + 1, h + 1)))) {
uint32_t CONTEXT = line5;
CONTEXT |= line4 << 2;
CONTEXT |= line3 << 5;
CONTEXT |= line2 << 6;
CONTEXT |= line1 << 7;
if (pArithDecoder->IsComplete())
return nullptr;
bVal = pArithDecoder->Decode(&grContext[CONTEXT]);
}
GRREG->SetPixel(w, h, bVal);
line1 = ((line1 << 1) | GRREG->GetPixel(w + 2, h - 1)) & 0x07;
line2 = ((line2 << 1) | bVal) & 0x01;
line3 = ((line3 << 1) | GRREFERENCE->GetPixel(w - GRREFERENCEDX + 1,
h - GRREFERENCEDY - 1)) &
0x01;
line4 = ((line4 << 1) | GRREFERENCE->GetPixel(w - GRREFERENCEDX + 2,
h - GRREFERENCEDY)) &
0x07;
line5 = ((line5 << 1) | GRREFERENCE->GetPixel(w - GRREFERENCEDX + 2,
h - GRREFERENCEDY + 1)) &
0x03;
}
}
}
return GRREG;
}
std::unique_ptr<CJBig2_Image> CJBig2_GRRDProc::DecodeTemplate1Opt(
CJBig2_ArithDecoder* pArithDecoder,
JBig2ArithCtx* grContext) {
if (!GRREFERENCE->data())
return nullptr;
int32_t iGRW = static_cast<int32_t>(GRW);
int32_t iGRH = static_cast<int32_t>(GRH);
auto GRREG = std::make_unique<CJBig2_Image>(iGRW, iGRH);
if (!GRREG->data())
return nullptr;
int LTP = 0;
uint8_t* pLine = GRREG->data();
uint8_t* pLineR = GRREFERENCE->data();
intptr_t nStride = GRREG->stride();
intptr_t nStrideR = GRREFERENCE->stride();
int32_t GRWR = GRREFERENCE->width();
int32_t GRHR = GRREFERENCE->height();
if (GRREFERENCEDY < -GRHR + 1 || GRREFERENCEDY > GRHR - 1) {
GRREFERENCEDY = 0;
}
intptr_t nOffset = -GRREFERENCEDY * nStrideR;
for (int32_t h = 0; h < iGRH; h++) {
if (TPGRON) {
if (pArithDecoder->IsComplete())
return nullptr;
LTP = LTP ^ pArithDecoder->Decode(&grContext[0x0008]);
}
uint32_t line1 = (h > 0) ? pLine[-nStride] << 1 : 0;
int32_t reference_h = h - GRREFERENCEDY;
bool line1_r_ok = (reference_h > 0 && reference_h < GRHR + 1);
bool line2_r_ok = (reference_h > -1 && reference_h < GRHR);
bool line3_r_ok = (reference_h > -2 && reference_h < GRHR - 1);
uint32_t line1_r = line1_r_ok ? pLineR[nOffset - nStrideR] : 0;
uint32_t line2_r = line2_r_ok ? pLineR[nOffset] : 0;
uint32_t line3_r = line3_r_ok ? pLineR[nOffset + nStrideR] : 0;
if (!LTP) {
uint32_t CONTEXT = (line1 & 0x0380) | ((line1_r >> 2) & 0x0020) |
((line2_r >> 4) & 0x001c) | ((line3_r >> 6) & 0x0003);
for (int32_t w = 0; w < iGRW; w += 8) {
int32_t nBits = iGRW - w > 8 ? 8 : iGRW - w;
if (h > 0)
line1 = (line1 << 8) |
(w + 8 < iGRW ? pLine[-nStride + (w >> 3) + 1] << 1 : 0);
if (line1_r_ok)
line1_r =
(line1_r << 8) |
(w + 8 < GRWR ? pLineR[nOffset - nStrideR + (w >> 3) + 1] : 0);
if (line2_r_ok)
line2_r = (line2_r << 8) |
(w + 8 < GRWR ? pLineR[nOffset + (w >> 3) + 1] : 0);
if (line3_r_ok) {
line3_r =
(line3_r << 8) |
(w + 8 < GRWR ? pLineR[nOffset + nStrideR + (w >> 3) + 1] : 0);
} else {
line3_r = 0;
}
uint8_t cVal = 0;
for (int32_t k = 0; k < nBits; k++) {
int bVal = pArithDecoder->Decode(&grContext[CONTEXT]);
cVal |= bVal << (7 - k);
CONTEXT = ((CONTEXT & 0x018d) << 1) | (bVal << 6) |
((line1 >> (7 - k)) & 0x0080) |
((line1_r >> (9 - k)) & 0x0020) |
((line2_r >> (11 - k)) & 0x0004) |
((line3_r >> (13 - k)) & 0x0001);
}
pLine[w >> 3] = cVal;
}
} else {
uint32_t CONTEXT = (line1 & 0x0380) | ((line1_r >> 2) & 0x0020) |
((line2_r >> 4) & 0x001c) | ((line3_r >> 6) & 0x0003);
for (int32_t w = 0; w < iGRW; w += 8) {
int32_t nBits = iGRW - w > 8 ? 8 : iGRW - w;
if (h > 0)
line1 = (line1 << 8) |
(w + 8 < iGRW ? pLine[-nStride + (w >> 3) + 1] << 1 : 0);
if (line1_r_ok)
line1_r =
(line1_r << 8) |
(w + 8 < GRWR ? pLineR[nOffset - nStrideR + (w >> 3) + 1] : 0);
if (line2_r_ok)
line2_r = (line2_r << 8) |
(w + 8 < GRWR ? pLineR[nOffset + (w >> 3) + 1] : 0);
if (line3_r_ok) {
line3_r =
(line3_r << 8) |
(w + 8 < GRWR ? pLineR[nOffset + nStrideR + (w >> 3) + 1] : 0);
} else {
line3_r = 0;
}
uint8_t cVal = 0;
for (int32_t k = 0; k < nBits; k++) {
int bVal = GRREFERENCE->GetPixel(w + k, h);
if (!(TPGRON && (bVal == GRREFERENCE->GetPixel(w + k - 1, h - 1)) &&
(bVal == GRREFERENCE->GetPixel(w + k, h - 1)) &&
(bVal == GRREFERENCE->GetPixel(w + k + 1, h - 1)) &&
(bVal == GRREFERENCE->GetPixel(w + k - 1, h)) &&
(bVal == GRREFERENCE->GetPixel(w + k + 1, h)) &&
(bVal == GRREFERENCE->GetPixel(w + k - 1, h + 1)) &&
(bVal == GRREFERENCE->GetPixel(w + k, h + 1)) &&
(bVal == GRREFERENCE->GetPixel(w + k + 1, h + 1)))) {
if (pArithDecoder->IsComplete())
return nullptr;
bVal = pArithDecoder->Decode(&grContext[CONTEXT]);
}
cVal |= bVal << (7 - k);
CONTEXT = ((CONTEXT & 0x018d) << 1) | (bVal << 6) |
((line1 >> (7 - k)) & 0x0080) |
((line1_r >> (9 - k)) & 0x0020) |
((line2_r >> (11 - k)) & 0x0004) |
((line3_r >> (13 - k)) & 0x0001);
}
pLine[w >> 3] = cVal;
}
}
pLine += nStride;
if (h < GRHR + GRREFERENCEDY)
pLineR += nStrideR;
}
return GRREG;
}